基于AD9208的高速采集电路设计

针对大带宽采样需求,设计了基于AD9208的高速采集电路,通过分析时钟抖动,噪声等因素对采集电路的影响,设计了相关电路,包括低抖动时钟电路、模拟信号输入电路、电源电路,并测试了在不同输入频率下,AD9208的无杂散动态范围.     

Novel and Potential Small Molecule Scaffolds as DYRK1A Inhibitors by Integrated Molecular Docking-Based Virtual Screening and Dynamics Simulation Study

The dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) is a novel, promising and emerging biological target for therapeutic intervention in neurodegenerative diseases, especially in Alzheimer’s disease (AD). The molMall database, comprising rare, diverse and unique compounds, was explored for molecular docking-based virtual screening against the DYRK1A protein, in order to find out potential inhibitors. Ligands exhibiting hydrogen bond interactions with key amino acid residues such as Ile165, Lys188 (catalytic), Glu239 (gk+1), Leu241 (gk+3), Ser242, Asn244, and Asp307, of the target protein, were considered potential ligands. Hydrogen bond interactions with Leu241 (gk+3) were considered key determinants for the selection. High scoring structures were also docked by Glide XP docking in the active sites of twelve DYRK1A related protein kinases, viz. DYRK1B, DYRK2, CDK5/p25, CK1, CLK1, CLK3, GSK3β, MAPK2, MAPK10, PIM1, PKA, and PKCα, in order to find selective DYRK1A inhibitors. MM/GBSA binding free energies of selected ligand–protein complexes were also calculated in order to remove false positive hits. Physicochemical and pharmacokinetic properties of the selected six hit ligands were also computed and related with the proposed limits for orally active CNS drugs. The computational toxicity webserver ProTox-II was used to predict the toxicity profile of selected six hits (molmall IDs 9539, 11352, 15938, 19037, 21830 and 21878). The selected six docked ligand–protein systems were exposed to 100 ns molecular dynamics (MD) simulations to validate their mechanism of interactions and stability in the ATP pocket of human DYRK1A kinase. All six ligands were found to be stable in the ATP binding pocket of DYRK1A kinase.     

基于AD9959的频率合成器设计及其应用

AD9959是ADI公司推出的一款高性能的四通道DDS芯片,其最高采样速率为500 Msample/S,每个通道具有独立的32 bit频率控制字,14 bit相位控制字和10 bit DAC.利用其同步性能良好、频率分辨高、控制方式灵活的性能特点,根据Galileo/GPS高精度伪卫星系统的要求设计了一款频率合成器.在设计过程中引入ADS软件辅助分析和仿真,该频率合成器能满足系统杂波抑制、相位噪声等各项指标要求.     

Verbenalin Reduces Amyloid-Beta Peptide Generation in Cellular and Animal Models of Alzheimer’s Disease

Verbenalin, among the major constituents of Verbena officinalis, has been reported to exhibit sleep-promoting and antioxidant activities. This study demonstrates the effects of verbenalin on amyloid-beta (Aβ) peptide generation in Swedish mutant amyloid precursor protein (APP)-overexpressing Neuro2a cells (SweAPP/N2a) and in Alzheimer’s disease (AD) animal models. We further performed molecular biological analyses of these in vitro and in vivo models of AD. The effects of verbenalin were assessed based on the expression of factors related to Aβ peptide production using Western blotting, enzyme-linked immunosorbent assay, and immunohistochemistry (IHC). The intracellular expression and release of APP protein were both decreased by verbenalin treatment in SweAPP/N2a cells. Thus, the production of Aβ peptides was decreased. Compared to those in AD transgenic (Tg) mice, IHC revealed that verbenalin-treated animals showed decreased Aβ and tau expression levels in the hippocampus. In addition, verbenalin restored the expression of brain-derived neurotrophic factor (BDNF) in the hippocampus of AD animal models. These findings suggest that verbenalin may decrease Aβ formation both in vitro and in vivo. Verbenalin may also help improve the pathological hallmarks of AD.     

用于检测红外焦平面阵列探测器信号的高速数据采集系统

利用12位A/D转换器AD9220,设计了一种由单片机控制的可用于红外焦平面阵列探测器信号检测的数据采集系统.该系统电路结构简单,而且其数据采集与存储完全靠硬件实现,其数据采样频率只取决于所选用的A/D转换器,而不受单片机速度的影响,因而可实现高速采集.在具体的应用中取得了较为满意的结果.     

一种基于DDS AD9832的带噪声低频信号源设计

直接数字频率合成技术可提供快速的信号建立时间,纯净的信号频谱,得到越来越广泛的应用。介绍了一种基于DDS AD9832的带噪声信号发生器,介绍了AD9832产生信号的原理,m序列产生伪噪声的过程,系统的硬件以及软件设计,给出了AD9832控制程序源代码。     

带有多种参数输出的测试装置

介绍了带液晶显示的多参数输出测试装置，该系统由89C52微处理器和12位A／D转换芯片AD574及12位D／A转换芯片AD7522实现，并带有RS—232通信接口和CAN总线，便于组成DCS或FCS系统。     

高速高精度模数转换器AD9244在软件无线电中的应用

AD9244是AD公司生产的14bit高速高精度的AD转换器。它有750MHz的输入带宽,最高允许抽样速率达到65MHz,其体积小、功耗低、精度高。专门应用于峰峰值小于2V的小信号的模数转换。文中介绍了AD9244的主要特点以及典型应用电路,在此基础上,给出了一个AD9244在数字中频软件无线电实验系统中的应用实例,同时指出了AD9244在应用过程中的注意事项。     

基于ATmega128和μC／OS-II的在线钠离子分析仪的设计

阐述了一种智能在线钠离子分析仪的软硬件设计。采用灵敏度高、稳定性强的电化学传感器。硬件应用低矧高性能的微控制器及外围器件,软件采用μC／OS-II操作系统。整个系统具有精度高、检测速度快、功耗低、稳定性强,操作界面友好等优点。     

Electronic polarizability-based stereochemical model for Sharpless AD reactions

Softness really is the hard force! Reported here was the critical yet long-overlooked role of electronic polarizability (i.e., softness) effect in controlling absolute stereochemical courses of general asymmetric induction events. Thus, a sensitive dependence of the sense of chiral induction on an alkene substrate’s substituent electronic polarizability character was uncovered from a range of structurally highly comparable Sharpless asymmetric dihydroxylation (AD) systems, from which a new polarizability-based stereochemical model of predictive power was suggested.